大锻件内部脆性夹杂物边界原生微裂纹闭合应力条件  

Stress Condition of Original Micro-cracks Closure of Internal Brittle Inclusion Boundary for Heavy Forgings

作　　者：李骏[1] 胡红磊 曹峰华[3] 张如林[3] 

机构地区：[1]上海理工大学机械工程学院,上海200093 [2]燕山大学机械工程学院,河北秦皇岛066004 [3]上海电机学院机械学院,上海200245

出　　处：《热加工工艺》2016年第1期147-150,共4页Hot Working Technology

基　　金：上海市教育委员会科研创新项目(12AZ02)

摘　　要：大锻件内部脆性夹杂物边界裂纹是影响其疲劳寿命与冲击性能的主要缺陷。热锻过程中脆性夹杂物周围区域的应力场是影响裂纹闭合的关键因素。为了研究应力场对裂纹闭合的影响,给出了平均球应力度的定义及数学表达式。以平均球应力度为判据,使用Deform软件研究了应力场对脆性夹杂物边界裂纹的影响规律。结果表明:脆性夹杂物边界裂纹对平均球应力度的相关度高;随平均球应力度代数值的减小,脆性夹杂物边界裂纹的尺寸减小,当平均球应力度代数值小于-2.32时,脆性夹杂物边界微裂纹完全闭合。在Gleeble-3180热模拟试验机上,利用专门的试件和型砧进行了1220℃热压缩变形试验,试验结果与数值模拟结果基本吻合。Cracks of boundary in internal brittle inclusion for heavy forgings are main defects of the influencing the fatigue life and the impact properties. In hot forging processes, the stress field around a brittle inclusion is one of the key factors for crack closure. In order to study influence of the stress field on crack closure, the definition of average relative spherical stress（ARSS） and its mathematical expression were given. Taking ARSS as the criterion, the influences of stress fields on crack in brittle inclusion boundary were investigated by using Deform software. The results show that brittle inclusion boundary cracks on the ARSS correlation is higher. Brittle inclusion boundary crack size reduces with the decrease of the algebraic value of the ARSS. When the ARSS algebraic value is less than-2.32, the brittle inclusion boundary micro-crack can be closed completely. Hot compression test at 1220℃ were done by using special specimens and anvils on a Gleeble-3180 thermo-mechanical simulator. Experimental results agree well with the numerical ones.

关 键 词：平均球应力度 大锻件 脆性夹杂物 微裂纹 

分 类 号：TG306[金属学及工艺—金属压力加工] TG156